The off-shore drilling of oil and gas wells in the ocean bottom is carried out from fixed or floating platforms or floating vessels. To carry out these operations, it is necessary to connect the drilling platform located at the surface to the ocean bottom by means of an extension tube, often called a "riser". This tube, consisting of numerous elements joined together end to end, serves mainly for channeling the drilling mud and guiding the drill rods.
To connect these elements, couplings of the bayonet type are used, and these incorporate a locking collar arranged outside the elements of the extension tube which are to be connected.